[x264-devel] about single layer video coding and scalable video coding

[Loic Le Loarer]

Hi,

On Thursday June 18 2009 at 12:30:26 PM +0200, 武南龚 wrote:
> thank you so much. I'm a little puzzled by the sentence below, can you give
> me some explanation.
> 
> Yes, temporal scalability is just a single layer with non-reference
> frames at regular intervals.
> _______________________________________
> 
> besides, x264 doesn't support SVC, can I treat the single layer coded video
> as a temporal scalable video coded one?

Yes, you can do that if the coded stream has the correct properties. For
example, do be a correct temporal scalable video sequence with 2 layers,
the base layer at 15fps and the second at 30fps, it is enough to have
the following sequence of pictures in display order (using old MPEG2
style for references):

I B P B P B P...

The base layer contains only the I and P pictures, the second layer adds
the B pictures.

Using x264, it is possible to generate such a sequence using the
following options (or similar):

 --bframes 1 --b-adapt 0 --ref 2

Using the --b-pyramid option, it is also probably possible to generate
a 3 layers stream, the first layer containning I/P frames, the second
reference B frames and the third non-reference B frames.

Once you have the generated the sequence using x264, you can turn it to
a real SVC sequence with temporal scalability by just adding the correct
SEI messages and may be changing some SPS or PPS parameters. I don't
know any tools whch can to this, but it isn't difficult to write this,
it could even be done directly in x264 and proposed for inclusion I
guess if there is interess in such a feature.

Best regards.

-- 
Loic

Only a very small fraction of our DNA does anything; the rest is all
comments and ifdefs.

> and is there any other tools similar to x264 that support SVC?
> 
> thank you!
> 
> 
> 
> 2009/6/18 Måns Rullgård <mans at mansr.com>
> 
> > 武南龚 <nangergong at gmail.com> writes:
> >
> > > hi,all
> > >
> > >   I'm using x.264 in linux now, I want to know which command line
> > argument
> > > decides whether the encoding is single layer video coding or scalable
> > video
> > > coding?
> > > and how to encode videos using different scalable video coding (temporal
> > > ,spatial and PSNR)?
> >
> > SVC is not supported in x264.
> >
> > > besides, is there any difference between single layer video coding and
> > > temporal scalable video coding? I thought they are the same
> >
> > Yes, temporal scalability is just a single layer with non-reference
> > frames at regular intervals.
> >
> > --
> > Måns Rullgård
> > mans at mansr.com
> > _______________________________________________
> > x264-devel mailing list
> > x264-devel at videolan.org
> > http://mailman.videolan.org/listinfo/x264-devel
> >
> 
> 
> 
> -- 
>                                       此致
>                         敬礼
> 
>                            龚武南
> 
> GongWunan
> 
> School of Electronic and Information Engineering
> Xi'an Jiaotong University,
> Xi'an 710049, People's Republic of China
> ^
> Computer and Communication Networks Engineering
> Politecnico di Torino,
> TORINO 10138,Italy
> Tel:+39-3881278481

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